Comment 48 for bug 768184

Issue is still marked as open upstream, and we've had one instance on precise, so evidently the bug is still out there.

  https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/914131

From the upstream bug report: "In essence, it seems that stale DPMS properties (kernel bug 24982), which normally just result in a blank screen, can in some situations result in a crash/hang."